Make std::scoped_allocator_adaptor's OUTERMOST recursive

Make std::scoped_allocator_adaptor's OUTERMOST recursive

	* doc/xml/manual/status_cxx2011.xml: Update status.
	* include/std/scoped_allocator (__outer_allocator_t, __outermost_type):
	New helpers for recursive OUTERMOST.
	(__outermost): Use __outermost_type::_S_outermost.
	(__do_outermost, scoped_allocator_adaptor::__outermost_type): Remove.
	(scoped_allocator_adaptor::__outermost_alloc_traits): Use new
	__outermost_type helper.
	* testsuite/20_util/scoped_allocator/outermost.cc: New test.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@240844 138bc75d-0d04-0410-961f-82ee72b054a4